1 files changed, 270 insertions, 0 deletions
diff --git a/arch/arm64/kvm/pkvm.c b/arch/arm64/kvm/pkvm.c
new file mode 100644
index 000000000000..b7be96a53597
--- /dev/null
+++ b/arch/arm64/kvm/pkvm.c
@@ -0,0 +1,270 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020 - Google LLC
+ * Author: Quentin Perret <qperret@google.com>
+ */
+
+#include <linux/init.h>
+#include <linux/kmemleak.h>
+#include <linux/kvm_host.h>
+#include <linux/memblock.h>
+#include <linux/mutex.h>
+#include <linux/sort.h>
+
+#include <asm/kvm_pkvm.h>
+
+#include "hyp_constants.h"
+
+DEFINE_STATIC_KEY_FALSE(kvm_protected_mode_initialized);
+
+static struct memblock_region *hyp_memory = kvm_nvhe_sym(hyp_memory);
+static unsigned int *hyp_memblock_nr_ptr = &kvm_nvhe_sym(hyp_memblock_nr);
+
+phys_addr_t hyp_mem_base;
+phys_addr_t hyp_mem_size;
+
+static int cmp_hyp_memblock(const void *p1, const void *p2)
+{
+	const struct memblock_region *r1 = p1;
+	const struct memblock_region *r2 = p2;
+
+	return r1->base < r2->base ? -1 : (r1->base > r2->base);
+}
+
+static void __init sort_memblock_regions(void)
+{
+	sort(hyp_memory,
+	     *hyp_memblock_nr_ptr,
+	     sizeof(struct memblock_region),
+	     cmp_hyp_memblock,
+	     NULL);
+}
+
+static int __init register_memblock_regions(void)
+{
+	struct memblock_region *reg;
+
+	for_each_mem_region(reg) {
+		if (*hyp_memblock_nr_ptr >= HYP_MEMBLOCK_REGIONS)
+			return -ENOMEM;
+
+		hyp_memory[*hyp_memblock_nr_ptr] = *reg;
+		(*hyp_memblock_nr_ptr)++;
+	}
+	sort_memblock_regions();
+
+	return 0;
+}
+
+void __init kvm_hyp_reserve(void)
+{
+	u64 hyp_mem_pages = 0;
+	int ret;
+
+	if (!is_hyp_mode_available() || is_kernel_in_hyp_mode())
+		return;
+
+	if (kvm_get_mode() != KVM_MODE_PROTECTED)
+		return;
+
+	ret = register_memblock_regions();
+	if (ret) {
+		*hyp_memblock_nr_ptr = 0;
+		kvm_err("Failed to register hyp memblocks: %d\n", ret);
+		return;
+	}
+
+	hyp_mem_pages += hyp_s1_pgtable_pages();
+	hyp_mem_pages += host_s2_pgtable_pages();
+	hyp_mem_pages += hyp_vm_table_pages();
+	hyp_mem_pages += hyp_vmemmap_pages(STRUCT_HYP_PAGE_SIZE);
+	hyp_mem_pages += hyp_ffa_proxy_pages();
+
+	/*
+	 * Try to allocate a PMD-aligned region to reduce TLB pressure once
+	 * this is unmapped from the host stage-2, and fallback to PAGE_SIZE.
+	 */
+	hyp_mem_size = hyp_mem_pages << PAGE_SHIFT;
+	hyp_mem_base = memblock_phys_alloc(ALIGN(hyp_mem_size, PMD_SIZE),
+					   PMD_SIZE);
+	if (!hyp_mem_base)
+		hyp_mem_base = memblock_phys_alloc(hyp_mem_size, PAGE_SIZE);
+	else
+		hyp_mem_size = ALIGN(hyp_mem_size, PMD_SIZE);
+
+	if (!hyp_mem_base) {
+		kvm_err("Failed to reserve hyp memory\n");
+		return;
+	}
+
+	kvm_info("Reserved %lld MiB at 0x%llx\n", hyp_mem_size >> 20,
+		 hyp_mem_base);
+}
+
+static void __pkvm_destroy_hyp_vm(struct kvm *host_kvm)
+{
+	if (host_kvm->arch.pkvm.handle) {
+		WARN_ON(kvm_call_hyp_nvhe(__pkvm_teardown_vm,
+					  host_kvm->arch.pkvm.handle));
+	}
+
+	host_kvm->arch.pkvm.handle = 0;
+	free_hyp_memcache(&host_kvm->arch.pkvm.teardown_mc);
+}
+
+/*
+ * Allocates and donates memory for hypervisor VM structs at EL2.
+ *
+ * Allocates space for the VM state, which includes the hyp vm as well as
+ * the hyp vcpus.
+ *
+ * Stores an opaque handler in the kvm struct for future reference.
+ *
+ * Return 0 on success, negative error code on failure.
+ */
+static int __pkvm_create_hyp_vm(struct kvm *host_kvm)
+{
+	size_t pgd_sz, hyp_vm_sz, hyp_vcpu_sz;
+	struct kvm_vcpu *host_vcpu;
+	pkvm_handle_t handle;
+	void *pgd, *hyp_vm;
+	unsigned long idx;
+	int ret;
+
+	if (host_kvm->created_vcpus < 1)
+		return -EINVAL;
+
+	pgd_sz = kvm_pgtable_stage2_pgd_size(host_kvm->arch.mmu.vtcr);
+
+	/*
+	 * The PGD pages will be reclaimed using a hyp_memcache which implies
+	 * page granularity. So, use alloc_pages_exact() to get individual
+	 * refcounts.
+	 */
+	pgd = alloc_pages_exact(pgd_sz, GFP_KERNEL_ACCOUNT);
+	if (!pgd)
+		return -ENOMEM;
+
+	/* Allocate memory to donate to hyp for vm and vcpu pointers. */
+	hyp_vm_sz = PAGE_ALIGN(size_add(PKVM_HYP_VM_SIZE,
+					size_mul(sizeof(void *),
+						 host_kvm->created_vcpus)));
+	hyp_vm = alloc_pages_exact(hyp_vm_sz, GFP_KERNEL_ACCOUNT);
+	if (!hyp_vm) {
+		ret = -ENOMEM;
+		goto free_pgd;
+	}
+
+	/* Donate the VM memory to hyp and let hyp initialize it. */
+	ret = kvm_call_hyp_nvhe(__pkvm_init_vm, host_kvm, hyp_vm, pgd);
+	if (ret < 0)
+		goto free_vm;
+
+	handle = ret;
+
+	host_kvm->arch.pkvm.handle = handle;
+
+	/* Donate memory for the vcpus at hyp and initialize it. */
+	hyp_vcpu_sz = PAGE_ALIGN(PKVM_HYP_VCPU_SIZE);
+	kvm_for_each_vcpu(idx, host_vcpu, host_kvm) {
+		void *hyp_vcpu;
+
+		/* Indexing of the vcpus to be sequential starting at 0. */
+		if (WARN_ON(host_vcpu->vcpu_idx != idx)) {
+			ret = -EINVAL;
+			goto destroy_vm;
+		}
+
+		hyp_vcpu = alloc_pages_exact(hyp_vcpu_sz, GFP_KERNEL_ACCOUNT);
+		if (!hyp_vcpu) {
+			ret = -ENOMEM;
+			goto destroy_vm;
+		}
+
+		ret = kvm_call_hyp_nvhe(__pkvm_init_vcpu, handle, host_vcpu,
+					hyp_vcpu);
+		if (ret) {
+			free_pages_exact(hyp_vcpu, hyp_vcpu_sz);
+			goto destroy_vm;
+		}
+	}
+
+	return 0;
+
+destroy_vm:
+	__pkvm_destroy_hyp_vm(host_kvm);
+	return ret;
+free_vm:
+	free_pages_exact(hyp_vm, hyp_vm_sz);
+free_pgd:
+	free_pages_exact(pgd, pgd_sz);
+	return ret;
+}
+
+int pkvm_create_hyp_vm(struct kvm *host_kvm)
+{
+	int ret = 0;
+
+	mutex_lock(&host_kvm->arch.config_lock);
+	if (!host_kvm->arch.pkvm.handle)
+		ret = __pkvm_create_hyp_vm(host_kvm);
+	mutex_unlock(&host_kvm->arch.config_lock);
+
+	return ret;
+}
+
+void pkvm_destroy_hyp_vm(struct kvm *host_kvm)
+{
+	mutex_lock(&host_kvm->arch.config_lock);
+	__pkvm_destroy_hyp_vm(host_kvm);
+	mutex_unlock(&host_kvm->arch.config_lock);
+}
+
+int pkvm_init_host_vm(struct kvm *host_kvm)
+{
+	mutex_init(&host_kvm->lock);
+	return 0;
+}
+
+static void __init _kvm_host_prot_finalize(void *arg)
+{
+	int *err = arg;
+
+	if (WARN_ON(kvm_call_hyp_nvhe(__pkvm_prot_finalize)))
+		WRITE_ONCE(*err, -EINVAL);
+}
+
+static int __init pkvm_drop_host_privileges(void)
+{
+	int ret = 0;
+
+	/*
+	 * Flip the static key upfront as that may no longer be possible
+	 * once the host stage 2 is installed.
+	 */
+	static_branch_enable(&kvm_protected_mode_initialized);
+	on_each_cpu(_kvm_host_prot_finalize, &ret, 1);
+	return ret;
+}
+
+static int __init finalize_pkvm(void)
+{
+	int ret;
+
+	if (!is_protected_kvm_enabled() || !is_kvm_arm_initialised())
+		return 0;
+
+	/*
+	 * Exclude HYP sections from kmemleak so that they don't get peeked
+	 * at, which would end badly once inaccessible.
+	 */
+	kmemleak_free_part(__hyp_bss_start, __hyp_bss_end - __hyp_bss_start);
+	kmemleak_free_part_phys(hyp_mem_base, hyp_mem_size);
+
+	ret = pkvm_drop_host_privileges();
+	if (ret)
+		pr_err("Failed to finalize Hyp protection: %d\n", ret);
+
+	return ret;
+}
+device_initcall_sync(finalize_pkvm);